Cruz Sr. was a citizen of Cuba when Ted was born. Cruz senior became a naturalized citizen of Canada some time later (a year or three), and at that moment, Cruz Sr. lost his Cuban citizenship. Cuba flat out rejects dual citizenship, so naturalizing elsewhere cuts off his Cuban citizenship without a formal renunciation.
At birth, Ted was indeed a citizen of Cuba, just the same as he was a citizen of the US. He is not a NBC of any country, being of mixed heritage at birth (country, mother, and father none the same).
This has been discussed on FR for a couple weeks anyway.
Thanks. I missed the Cuban part of the discussion, only focused on the American mother / born in Canada part. I never considered the triple citizen at birth, only dual citizen.
-PJ